1. Field of the Invention
This invention relates to the preparation of TiO.sub.2 from sodium titanate by reacting with sulfuric acid and calcining.
2. Description of the Prior Art
Two processes are in general use for making TiO.sub.2. The older sulfate process involves dissolving a titanium source, e.g. ilmenite, in sulfuric acid and then hydrolyzing the titanium sulfate to TiO.sub.2, which is then calcined. The other process is the chloride process wherein rutile is chlorinated to form TiCl.sub.4 which is then oxidized to form TiO.sub.2. Both processes are described in greater detail in Kirk-Othmer "Encyclopedia of Chemical Technology", 2nd Edition, Vol. 20, pp. 392-410. Attention is also directed to a review of processes for making artificial rutile by Henn et al, entitled "A Review of Proposed Processes for Making Rutile Substitutes", Bureau of Mines Information Circular 8450, 1970, 27pp.
In the prior related application Ser. No. 260,262 a process is described for producing sodium titanate from ilmenite by smelting the latter with a carbonaceous reducing agent and an alkali metal borate flux. The sodium titanate is then subjected to the conventional sulfate process for recovering TiO.sub.2.